June 9, 2025 — Islam are the fastest-growing religious group globally, adding 347 million followers between 2010 and 2020, according to the Pew Research Center’s latest Global Religious Landscape study released Monday.
The religiously unaffiliated, or “nones,” followed as the second-fastest-growing group, while Christianity, though still the largest religion, saw its global share decline.
The comprehensive report, the second edition of a study launched in 2010, draws from 2,700 data sources, including censuses and surveys across 201 countries. It examines demographic trends like fertility, mortality, and religious switching to map changes in the world’s religious makeup.
The global Muslim population grew primarily due to higher birth rates, not conversions, said Conrad Hackett, a senior demographer at Pew. “Muslims are having children at a greater number than Muslims are dying,” he told RNS.
The Asia-Pacific region, home to the largest Muslim population, saw a 16.2% increase. Muslims dominate in the Middle East-North Africa (94.2%) and make up 33% of sub-Saharan Africa’s population.
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Christianity, with 2.3 billion adherents (29% of the global population), grew by 122 million but dropped 1.8% as a share of the world’s population. The faith remains the most geographically dispersed, though it declined in Europe, North America, and other Western regions. Hackett noted significant disaffiliation, with many raised Christian no longer identifying with the faith.
The religiously unaffiliated now form the third-largest group, comprising 24.2% of the global population. Their numbers surged in North America (up 13 points to 30.2%), Europe (up 6.6 points to 25.3%), and Latin America (up 4.1 points). Asia-Pacific hosts 78% of nones, with 67% in China, though capturing religiosity there remains complex, Hackett said.
Buddhism was the only major religion to shrink, losing 19 million followers due to disaffiliation in East Asia. The study notes that many who practice Buddhist traditions may not identify as Buddhist.
Hindus, the fourth-largest group at 14.9% of the global population, grew significantly in the Middle East-North Africa (62%) due to migration and in North America (55%). Most Hindus (95%) live in India. The Jewish population, the smallest group at 0.2%, grew 6% to 15 million, with 45.9% residing in Israel.
The study, delayed by the COVID-19 pandemic, analyzed religious switching for the first time, using data from 117 countries on adults aged 18 to 54. It highlights how demographic factors like age structure and education shape the future of religious groups.
Pew’s findings underscore the dynamic interplay of population growth and disaffiliation reshaping the global religious landscape, with implications for cultural and social trends worldwide.
